This invention relates to a trigger for the ignition system of an internal combustion engine and, in particular, to a magnet triggered ignition system for four-stroke engines in racing vehicles.
The prior art discloses various magnet triggered ignition systems which utilize magnet-containing rotors which are ultimately connected to and rotate in unison with the crankshaft of an internal combustion engine. For example, Williams U.S. Pat. No. 3,875,920, Kopera U.S. Pat. No. 4,106,460, Schmiedel U.S. Pat. No. 3,518,978 and Hino et al. U.S. Pat. No. 4,499,888 disclose that the rotors on which the magnets are mounted are located in the distributor. Burson U.S. Pat. No. 3,554,179 and Finch U.S. Pat. No. 3,521,611 disclose the magnet-containing rotors as being incorporated into the flywheel of the engine, while Erhard U.S. Pat. No. 4,428,333 discloses the magnet-containing rotor as being incorporated into the fan of the engine. Other prior art patents do not specify any particular location for the magnet-containing rotor.
Many racing vehicles utilize stock, four-stroke engines which are heavily modified. For instance, these engines may utilize non-stock internal and external components such as crankshafts, cam shafts, etc. Where nonstock, non-counterbalanced crankshafts are installed, such vehicles often employ a counterbalancing hub attached to one end of the crankshaft to dynamically balance the engine and reduce vibration. Typically, this hub is attached to the crankshaft in place of the pulley which normally drives stock engine accessories such as the water pump, alternator, power steering pump, air conditioner compressor, etc., since such accessories are either not used (because of weight considerations) or are not driven by a belt off the engine (because of power consumption). The use of magnet triggered ignition systems is desirable in racing vehicles since it saves weight and increases performance. It has even been known to bolt a rotor plate containing magnets to the balancer hub in order to trigger a sensor in such ignition systems. However, such rotors have had a tendency to "walk", i.e. to change orientation with respect to the crankshaft under repeated use and abuse so that they must be frequently readjusted to keep proper ignition timing. Furthermore, such bolt-on accessories add undesired weight to the engine and car.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a magnetic ignition pickup trigger which is particularly suitable for the engines of racing vehicles.
It is another object of the present invention to provide an ignition system for racing vehicles which may be easily installed in existing vehicles.
It is a further object of the present invention to provide a magnetic ignition pickup trigger which reduces undesirable weight in the racing vehicle.
It is yet another object of the present invention to provide a magnetic ignition pickup trigger which retains its proper orientation with respect to the crankshaft and timing after repeated useage.
It is a further object of the present invention to provide a magnetic ignition pickup trigger which dynamically balances non-stock racing crankshafts in internal combustion engines.